Abstract only

Changes in the protein content and functional characteristics of photosynthetic membranes upon the impact of various Na CI concentrations were studied. To evaluate the effect of salinity stress on wheat seedlings, NaCI was applied at the rates of 100, 150,200 and 250 mM. Polypeptide in the area of34 kDa is found in the control seedlings of wheat variety Barakatli-95 at low rates. However, its volume grows together with increase of salt concentration in the medium, particularly at the level of 250 mM NaCI. Synthesis of the polypeptide from Mr 1.5 kDa also intensifies with increase of the salt concentration. At the same time, no noticeable changes are observed in the composition and content of the light-absorbing complexes of photosynthetic membranes. In the low-temperature fluorescence (77K) spectrum of chloropalsts isolated from wheat seedlings and exposed to the action of 150 mM NaC1, the major band, which is localized at 740- 741 nm in control, shifts by 3-4 nm towards the short-wave region. Concurrently, the band intensity in the short- wave region reduces at 687 and 695 nm. These changes are particularly evident upon action of 200 mM NaCI, with the corresponding decrease in the ratio F736/F687. It may be supposed that the electrostatic action of salts on linker proteins FS 1 leads to the disaggregating of trimmers and the resultant disturbance of redistribution of energy between the photo-system 1 and photo-system 2.

English

0408|AGRIS 0401|AL-Wheat Program

Juan Carlos Mendieta

CIMMYT Publications Collection